The purpose of the steerable lightfield display (SLF) is to provide large-scale stereoscopic viewing to one or more binocular observers standing at various distances in front of a large display screen, while allowing each eye of each observer to simultaneously be shown a different image.
As display screens increase in size, it becomes prohibitively expensive to achieve the above-stated purpose by use of an electro-optically active screen, such as one composed of computer-switched liquid crystal elements. For this reason, the display described herein relies only on a passive display screen.
All active electro-optical elements are housed inside a set of specially designed projectors, each of which transmits its image, via the display screen, to only one eye of a single observer. In this way, N observers can view the same large screen, where N can be greater than one. Each of the 2N eyes (2 eyes per observer) can perceive a different and unique image. Each such “eye view” is not visible to the other 2N -1 eyes.
A single projector can also serve the function of multiple projectors, by time-multiplexing. In this variation, one projector sends K signals per moving image frame, in rapid sequence. During each sub-frame, that projector can accommodate K different observer eye positions. For example, if 60 images need to be displayed per second, and K=2, then one projector can accommodate two observer eye positions, by sending an image 120 times per second, alternating between the two targeted observers.
In this way, large-size custom stereoscopic viewing is supported for multiple simultaneous observers, upon a single passive display screen. This enabling mechanism also has other novel uses. For example, multiple observers can watch the same movie or interactive presentation simultaneously, with all figures and text labels customized in a way which is most appropriate for each observer, such as being translated into the language of that observer's choice, or showing sales figures, test scores, etc., appropriate to his or her situation. Also, a person giving a presentation can see his or her notes upon the screen, while those notes remain invisible to others in the room. Similarly, a presentation containing sensitive material can be given to different people who have different levels of security clearance, allowing only those persons who have the required level of permission to see certain privileged information in the presentation.
Also, the display allows a group of people to participate in remote teleconferences, so that participants at a remote location appear to participants within the room as though also present within the room. In this use, each eye of each participant within the room can see the remote participants from the correct viewpoint, as though each remote participant were at a consistent physical location within the room. Also, proper mutual eye contact can be maintained among all participants. Participants in the teleconference do not need to employ special eyewear.